TITLE:
Traffic Incident Management Performance Measures: Ranking Agencies on Roadway Clearance Time
AUTHORS:
Maroa Mumtarin, Skylar Knickerbocker, Theresa Litteral, Jonathan S. Wood
KEYWORDS:
Traffic Incident Management, Roadway Clearance Time, Performance Measures and Ranking, Agency Performance Evaluation, Tobit Regression Model
JOURNAL NAME:
Journal of Transportation Technologies,
Vol.13 No.3,
June
15,
2023
ABSTRACT: This
study develops a procedure to rank agencies based on their incident responses
using roadway clearance times for crashes. This analysis is not intended to
grade agencies but to assist in identifying agencies requiring more training or
resources for incident management. Previous NCHRP reports discussed usage of
different factors including incident severity, roadway characteristics, number
of lanes involved and time of incident separately for estimating the
performance. However, it does not tell us how to incorporate all the factors at
the same time. Thus, this study aims to account for multiple factors to ensure
fair comparisons. This study used 149,174 crashes from Iowa that occurred from
2018 to 2021. A Tobit regression model was used to find the effect of different
variables on roadway clearance time. Variables that cannot be controlled
directly by agencies such as crash severity, roadway type, weather conditions,
lighting conditions, etc., were included in the analysis as it helps to reduce
bias in the ranking procedure. Then clearance time of each crash is normalized
into a base condition using the regression coefficients. The normalization
makes the process more efficient as the effect of uncontrollable factors has
already been mitigated. Finally, the agencies were ranked by their average
normalized roadway clearance time. This ranking process allows agencies to
track their performance of previous crashes, can be used in identifying low performing
agencies that could use additional resources and training, and can be used to
identify high performing agencies to recognize for their efforts and
performance.